I use regular push lawnmowers to cut brush (1" or so in dia ) and clear tall weeds on rough ground. I use next to junk mowers. I put bigger wheels (12") on the rear of the mower and cut out the bottom front of the mower deck so that its even with the blade.

I use the mower to initially clean up an area where I find rocks, trash and other debris. After the first mowing I have to cut off the sapling stumps with a weed eater with blade and pick up the rocks and trash.